As for the copyright issue as mentioned in the previous post, it may not be totally "official", but simply putting a copy in an envelope which you send to yourself (and never open) can work as proof that you had it before anyone else!

That's been a nice side effect for me since cleaning up my diet to a high fruit, raw vegan diet a few months ago. So not quite fruitarian, but my love for fruit is quite strong & I can't wait to read your book!

If you haven't figured it out, you need to get an isbn number from the library of congress even if you self publish. This is a way of keeping everything legal. Sure you can skip it but if you send a copy to the LOC and they issue you and isbn this also confirms your copyright of the book.